The reduction of gas concentrations in broiler houses through ventilation: Assessment of the thermal and electrical energy consumption

Ammonia and carbon dioxide are the most relevant among the harmful gases present in broiler houses and their effects on animal health depend on concentration and exposure time. Inside these houses, increasing ventilation is the most common strategy adopted to control the concentration of these gases. This strategy is effective but increases electrical energy consumption (for fan operation) and thermal energy consumption (for inlet air heating). In this work, the variations of energy consumption due to the increase of ventilation to maintain ammonia and carbon dioxide concentrations below established thresholds were evaluated. To carry out this analysis, various parameters (e.g. indoor air temperature and gas concentrations) of a broiler house located in the Mediterranean area were monitored during a production cycle in the cool (winter) season in which outdoor air temperature varied between 2 and 25 °C. The assessment of the increase in the energy consumption for climate control was carried out using the Specific Fan Performance and a customised building energy simulation model. The analysis showed that during the monitored period, the established thresholds of gas concentrations were exceeded approximately 60% of the time. To maintain the desired gas concentrations, the ventilation flow rate should be increased by 9%. This variation in the ventilation flow rate entailed a rise in the energy consumption by about 10% for electrical energy and by about 14% for thermal energy. Maintaining the gas concentration below the established thresholds entails an extra cost of around 0.02 € per harvested broiler.